Drawing press



Jan. 7, 1930. R. B. TREER 1,742,673

DRAWING PRESS Filed Sept. 23, 1926 2 Sheets-Sheet 1 gw'uentoz Jan. 7, 1930. TREER 1,742,673

DRAWING PRESS Filgd Sept. 25. 1926 2 Sheets-Sheet 2 Fig. 3

holder preceding the work engaging move-- Patented Jan. 7, 1930,

ROSS B. TREER, or 'roLnno, 'onro, Assiqnon TENT OFFICE THE TOLEDOMACHIN'E & TOOL COM- PANY, or TOLEDQ, okraalc n'ronn'rion or OHIO Application filed sweetest-3.1m. Serial No. 137,334.

This invention relates to drawing presses and particularly to the means for imparting movements to the blank-holders thereof. 3 An object of the invention is the provision in a drawing press-of an 'improvedblankholder operating mechanism, which has'iconnection with and receives its power .from the main crank shaft of the press at the center thereof and transmits the power equally in opposite directions to the blank-holder from theforward central point, so that a perfectly balanced action is secured. v

A further object of the invention is the elimination of all slidesfrom blank-holder operating mechanisms of the class described.

A further object of the invention is to obtain a blank-holding movement of the blankment of the shaping plunger by simple and .eflicient means other than by advancing the throw of the main blank-holder operating crank relative to the operating for the shaping plunger, thus enabling all of the cranks of the crank shaft to project in the same direction and plane from the shaft axis and resulting in operating advantages.

Further objects and advantages of the invention will be apparent from the following detailed description.

While the invention in its broader aspect is capable of embodiment in numerous forms, a preferred embodiment thereof is illustrated in the accompanying drawings, in which,-

Figure 1' is a front elevation of a drawing press embodying the invention with parts broken away and with the blank-holder at the limit of its downward movement. Fig.

- 2 is a curve illustrating the movements and a relative period of dwell of the blank-holder.

Fig. 3 is a front elevation of the upper portion of the press, similar to Fig. 1, with the blank-holder and'shaping plunger in elevated positions. Fig. 4 is a section on the line 14 in Fig. 3. Fig. 5 is a section on the line 5-- 5 in Fig. 3, and Fig. 6 is a fragmentary section on the line 66 in Fig. 1.

Referring to the drawings, 1 designates a drawing press frame having the side uprights 2 and the top or crown portion 3 connecting the uprights. The customary blankholder 4: is uided for vertical reciprocatory movements etween the uprights, and the usual plunger 5 for the shaping die works 9 through and is guided by the blank-holder, as

well understood in the art. The usual crank shaft 6 of the press is journaled in the uprights 2 and in interposed bearing parts? depending from the crown 3, and is disposed in the center vertical plane of the blank-holder and plunger. The crank shaft is provided with like cranks 8 at opposite sides of its longitudinal center connected by pitmen 9 to the lunger5.

T e present invention resides in the mechanism for imparting the requisite reciprocatory movements and dwell to the blank-holder 4 from a revolution of a center crank 10 on the crank shaft 6. This crank is disposed ably projects in the same plane and direction from the crank shaft as the cranks 8, instead of being advanced with respect to the cranks 8 as is usually done to cause the movement of the blank-holder to precede that of the plunger. 5

YA pitman 11 .connects the crank 10 to one end ofa rocker or lever 12, the pivot 13 of which is fixedly mounted between the bearing parts 7 above the crank shaft with its axis parallel thereto. The other end of the rocker 12 is provided with a cross-pin 14. A pitman 15 extends upward from each end of said pin and connects to the short arm of a respective rocker lever 16. .The two rockers 16, only one of which is shown on the drawings, are mounted in equi-distantly spaced relation to the frame center at opposite sides thereof on fixed pivot pins 17 mounted in the frame crown 3 transversely of the crank shaft. Universal joint connecpitman-15, and the connected parts to permit the rocking of the connected levers 12 and 16 .in planes at right angles to each. other The levers 12 and 16 are both sub-' stantially straight, with the arms of the lever 12 approximately equal in length and with the outer arm of each lever 16 slightly longer than the inner arm.

The outer end of each lever 16 is connected 9o tions are provided between the ends of each by a downwardly extending link 18 to a re-. spective rocker arm 19 projecting inwardly withrespect to the frame 1 from the central portion of a shaft 20. This shaft is 'ournaled in the frame 1 above the crank-s aft 6 at right angles thereto andwith the vertical plane of its axis adjacent to the inner side of the associated frame upright 2. --The ends of eachshaft 20 project without the frame 1 at the front andback sides thereof and each carries a-rocker-arm 21. The arms 21- are slightly longer than the arms 19 and the rela-- tive planes of projection of the arms from the shafts are such that when the arms 21 are'in downwardly projecting vertical planes the arm 19 on the shaft therewith is inclined inward anddownward at approximately a angle'to the plane of the arms 21. When the rocker arms are in this position, the longitudinal axis of the associated link 18 aligns substantially with the longitudinal axis of the connected arm of the lever 16.

Each rocker arm 21 is connected to the re-' spective corner portion of the blank-holder 4 by a'link 22. When the blank-holder is at the limit of its down stroke,.the links 22 and connected rocker arms 21 are disposed 1n substantially vertical alignment, as shown in Fig. 1. In the present instance, the links 22 are connected to the blank-holder 4 through the medium of an adjusting frame 23, as well understood in the art.

It is evident that when the blank-holder 4' and plunger 5 are in elevated positions, the

parts of the'blank-holder operating mechanism will stand substantiallyin the relationship indicatedin Figs. 3 and 5 with the cranks ofthe crank-shaft 6 in the upper arcs of their movement, and that, as the cranks descend; from said upper position, the rockers 12 Wlll be rocked to effect an upward movement of the pitman 15 and a consequent rocking 9f the levers 16 to throw their outer ends downward and to effect a rocking of the shafts 2O to straighten out the connections2l 22 between said shafts and the blank holder, thereby moving the blank-holder to its lowered position. ,When the blank-holder has reached its lowered or work-holdinga-positlon, it stands at dwell for from 12L)? to 130 of a revolution of the crank-shaft by reason of the particular connection whichis employed between the crank-shaft and blank-holder. It is. necessary in presses of this type that the motion imparted to the blank-holder be uniform at all points in its movement and that all p'ointsof the blank-holder means travel at the same speed even though the work is such that it is unevenl distributed over the area of the shaping p unger, and this s possible with the mechanism employed.

It is important in the operation of-presses of this character that the blank-holder precede the shaping plunger m its downward stroke in order that the work may be gripped facture by allow and firmly held withan even pressure through that portion of the operating cycle in which the shaping plunger does its work. The

common practlcein this connection is to ad- Vance the throw of the crank which operates the blank-holder relative to the plunger operating cranks an amount necessary to accomplish this purpose. I have found, howi ever, that better results are obtained by maintaining the blank-holder and plungeroperating cranks of the crank-shaft in a common .plane of projection from the crank-shaft and movement of the blank-holder in advance of the plunger. In Figs. 5 and 6 the extent of offset of the pivot 13 from the vertical plane of the crank-shaft axis is indicated by the vertical lines a and b, the line apassing through the shaft axis and the line b passing through the pivot axis. With this arrangement the same advantage, so far as advancing the movement of the blank-holder with respect to the plunger is concerned, is obtained as by advancing the throw of one crank-arm of the shaft with respect to the others, and in addition-the crank-shaft is more evenly balanced and has the advantage of simplifying manug all of the cranks to be made in the same place.

The elimination of all slides from the powertransmitting mechanism between the crankshaft and blank-holder obviates the necessity of providing ground or smooth surfaces in the frame head for the slides or of providing separate guiding means in the frame head for such purpose, facilitates assembly and operating of the parts and lessens the liabilit of wear incident to the use of relatively sli ing contacting surfaces.

not limited to any specific construction, arrangement or form of the parts as it is capable of numerous modifications and changes without departing from the spirit of the claims.

Having thus described my invention, what 4 I claim as new and desire to secure by Letters Patent is: I

1. In a drawing press, a blank-holder, a

crank-shaft h'aving a center crank, a rockerv member vertically spaced from the'crank,

a pitman connecting the crank and one'end of sad rocker member, and two sets of means I wish. it understood that my invention is including rocker members having their axes j transverse to the axis of said crank shaft connecting the other end of the rocker member to opposite ends of the-.blank-holder for imparting predetermined reciprocatory movements to the blank-holder from rocking movements of saidmember.

2. In a drawing press, a blank-holder, a crank-shaft having a crank vertically spaced from and horizontally centered with respect to the blank-holder, a rocker lever vertically spaced from the crank, a pitman connecting the crank and lever, and two sets of mechanisms connecting the lever with opposite ends of the blank-holder for imparting prede termined reciprocatory movements to the blank-holder from rocking movements of the lever, each of said mechanisms including in successively connected arrangement outwardly from the said lever a link, a second lever,

a. second link,-a bell crank lever and a third link.

3. In a drawing press, a blank-holder, a crank-shaft having a crank vertically spaced from and horizontally centered with respect to the blank-holder, two rock shafts vertically rock-shaft and the associated end of the blankholder to impart reciprocatory movements to the blank-holder from rocking movements of the shaft, a main lever having its rocking axis parallel to the crankshaft axis, a separate connection between the main lever and each ofsaid other levers to impart rock ing movements from one to the other, and aconnection between the main .lever and crank for rocking the former from revoluble movements of the latter. I

4. In a drawing press, a crank shaft, a blank holder, and means for operating said blank holder, said means comprising, a rocker member with its rocking axis parallel to said crank shaft, a pitman connecting said rocker member and crank shaft, a rocker lever disposed above and at opposite sides of said rocker member, links connecting one end of said rocker member to said rocker levers, rock shafts spaced vertically from and disposed adjacent opposite ends of said crank shaft, lever and link connections between said rock shafts and adjacent rocker levers, and an operative connection between each rock shaft and the adjacent end of said blank holder.

5. In a drawing press, a blank holder, a crank shaft, rock shafts spaced vertically from said crank shaft and disposed transversely thereof at each end of the crank shaft,

a lever spaced vertically and inwardly from each rock shaft, a rocker member spaced vertically from the central portion of said crank shaft with its rocking axis disposed in parallel relationship'to the axis'of said crank shaft, an operative connection between said rocker member and crank shaft, and lever and link connections between said rocker member, each set of inwardly spaced levers, transverse shafts and the opposite ends of said blank holder.

6. In a drawing press, a blank holder, a crank shaft, a rocker member vertically, spaced from the central portion of said crank shaft, an operative connection between said rocker member and said crank shaft, a shaft spaced vertically from said crank shaft and disposed transversely thereof adjacent each end of the crank shaft, a rocker lever for each transverse shaft disposed thereabove and having its axis parallel to said'transverse shafts, and operative connections between said rocker member, transverse shafts, rocker.

levers and the opposite ends of the blank holder.

7.-In a drawing press, a blank-holder, a crank shaft, a rocker member vertically spaced from said crank shaft, an operative connection between said rocker member and crank shaft, a shaft disposed transverselyv of each end of said crank shaft, a rocker lever for each transverse shaft and spaced inwardly therefrom, andoperative connections respectively between said rocker member, rocker levers, transverse shafts and the ends of said blank holder.

crank shaft, a rocker member spaced verti- ,cally from .said crank shaft, an operative connection between said rocker member and crank shaft, a transverse shaft spaced vertically from said crank shaft and disposed transversel of each end of said crank shaft, a link an lever connection between each transverse shaft and the opposite ends of said blank holder, a rock shaft for each trans-' verse shaft spaced inwardly and vertically therefrom, and link and lever connections between each inwardly spaced. shaft and rocker member and adjacent transverse shaft.

9. In a drawing press, a blank-holder, a crank shaft having a central crank, a rocker member spaced from the crank, and an operating connection between the'crank and one' 8. In a drawing press; a blank-holder, a

end of saidrocker member, and two sets of means adjacent opposite end portions of said crank shaft, each including rocker members having their axes transverse to the axis of said crank shaft connecting the other end of the rocker member to opposite ends of the blank-holder for imparting predetermined reciprocatory movements to the blankholder from rocking movements of said first rocker member. I

In testimony whereof I have hereunto signed my name to this specification.

ROSS B.' TREER. 

